Imaging lens and imaging apparatus including the imaging lens

ABSTRACT

An imaging lens substantially consists, in order from an object side, five lenses of a first lens that has a positive refractive power and has a meniscus shape which is convex toward the object side, a second lens that has a negative refractive power, a third lens that has a negative refractive power, a fourth lens that has a positive refractive power, and a fifth lens that has a negative refractive power and has an object side surface and an image side surface which have aspheric shapes. Further, the imaging lens satisfies predetermined conditional expressions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fixed-focus imaging lens that formsan optical image of a subject on an imaging device, such as a chargecoupled device (CCD) and a complementary metal oxide semiconductor(CMOS), and to an imaging apparatus, such as a digital still camera, acellular phone with a camera, a mobile information terminal (PDA:Personal Digital Assistance), a smartphone, a tablet terminal, and amobile game machine, on which the imaging lens is mounted to performphotography.

2. Description of the Related Art

Recently, as personal computers have become popular in homes, digitalstill cameras which are capable of inputting image information aboutphotographed scenes, persons, and the like into the personal computershave spread rapidly. Further, a cellular phone, a smartphone, or atablet terminal in which a camera module for inputting images isinstalled has been increasing. Such apparatus having an imaging functionuses an imaging device, such as a CCD and a CMOS. Recently, because theimaging device has been miniaturized, there has been also a demand tominiaturize the whole of the imaging apparatus and an imaging lensmounted thereon. Further, since the number of pixels included in theimaging device has also been increasing, there has been a demand toenhance the resolution and performance of the imaging lens. For example,there has been a demand for performance corresponding to high resolutionof 5 megapixels or higher, and preferably performance corresponding tohigh resolution of 8 megapixels or higher.

To satisfy such demands, it can be considered that the imaging lens iscomposed of five or six lenses, which are a relatively large number oflenses. For example, International Patent Publication No. 12/063391(Patent Document 1) and Japanese Unexamined Patent Publication No.2010-282000 (Patent Document 2) propose an imaging lens composed of fivelenses. The imaging lens disclosed in Patent Documents 1 and 2substantially consists of, in order from an object side, five lenses ofa first lens that has a positive refractive power, a second lens thathas a negative refractive power, a third lens that has a negativerefractive power, a fourth lens that has a positive refractive power,and a fifth lens that has a negative refractive power.

SUMMARY OF THE INVENTION

In particular, for the imaging lenses used in apparatuses, of which thethickness has been decreased, such as a cellular phone, a smartphone ora tablet terminal, a demand to decrease the total length of the lens hasbeen increased more and more. Hence, it is necessary to further decreasethe total lengths of the imaging lenses disclosed in Patent Documents 1and 2.

The present invention has been made in view of the above-mentionedcircumstances and an object thereof is to provide an imaging lenscapable of achieving high imaging performance in the range from thecentral angle of view to the peripheral angle of view while achieving adecrease in the total length thereof. Another object of the presentinvention is to provide an imaging apparatus capable of obtaining aphotographed image with high resolution through the imaging lens whichis mounted thereon.

The imaging lens of the present invention is an imaging lenssubstantially consists of, in order from an object side, five lenses of:

a first lens that has a positive refractive power and has a meniscusshape which is convex toward the object side;

a second lens that has a negative refractive power;

a third lens that has a negative refractive power;

a fourth lens that has a positive refractive power; and

a fifth lens that has a negative refractive power and has an object sidesurface and an image side surface which have aspheric shapes,

wherein the following conditional expressions (1) and (2) are satisfied:

0.043<f/f45<0.186  (1),

and

0.961<f/f4<1.785  (2),

where

f is a composite focal length of a whole system,

f45 is a composite focal length of the fourth and fifth lenses, and

f4 is a focal length of the fourth lens.

According to the imaging lens of the present invention, in the imaginglens which is composed of five lenses as a whole, a configuration ofeach lens element of the first to fifth lenses is optimized. Therefore,it is possible to achieve a lens system that has high resolutionperformance while decreasing the total length thereof.

In the imaging lens of the present invention, the expression“substantially consisting of five lenses” means that the imaging lens ofthe present invention may include not only the five lenses but also alens which has substantially no refractive power, optical elements, suchas a stop and a cover glass, which are not a lens, mechanism parts, suchas a lens flange, a lens barrel, an imaging device and a hand shake blurcorrection mechanism, and the like. When the lens includes an asphericsurface, the reference sign of the surface shape and refractive power ofthe lens is considered in a paraxial region.

In the imaging lens of the present invention, by employing andsatisfying the following desirable configuration, it is possible to makethe optical performance thereof better.

In the imaging lens of the present invention, it is desirable that anintersection point between the image side surface of the third lens anda principal ray with a maximum angle of view be positioned on the objectside of an intersection point between the image side surface of thethird lens and an optical axis, and an intersection point between anobject side surface of the third lens and the principal ray with themaximum angle of view be positioned on the object side of anintersection point between the object side surface of the third lens andthe optical axis.

In the imaging lens of the present invention, it is desirable that thefifth lens have a meniscus shape which is convex toward the object side,and each of the object side surface and the image side surface has anaspheric shape which has at least one extreme point.

In the imaging lens of the present invention, it is desirable that amongabsolute values of respective focal lengths of the first to fifthlenses, an absolute value of a focal length of the third lens be themaximum.

In the imaging lens of the present invention, it is desirable that thefourth lens have a meniscus shape which is convex toward an image side.

It is desirable that the imaging lens of the present invention furtherinclude an aperture stop that is disposed on the object side of anobject side surface of the second lens.

It is desirable that the imaging lens of the present invention satisfyany of the following conditional expressions (1-1) to (2-2).

It should be noted that, as a desirable mode, any one of the conditionalexpressions (1-1) to (2-2) may be satisfied, or an arbitrary combinationthereof may be satisfied.

0.053<f/f45<0.178  (1-1)

0.063<f/f45<0.17  (1-2)

1<f/f4<1.681  (2-1)

1<f/f4<1.58  (2-2),

where

f is a composite focal length of a whole system,

f45 is a composite focal length of the fourth and fifth lenses, and

f4 is a focal length of the fourth lens.

The imaging apparatus of the present invention includes the imaging lensof the present invention.

According to the imaging lens of the present invention, in the imaginglens which is composed of five lenses as a whole, a configuration ofeach lens element is optimized, and particularly the shape of the fifthlens is appropriately formed. Therefore, it is possible to achieve alens system that has high resolution performance in the range from thecentral angle of view to the peripheral angle of view while decreasingthe total length thereof.

Further, according to the imaging apparatus of the present invention,imaging signals based on an optical image formed by the imaging lens ofthe present invention, which has high imaging performance, are output.Therefore, it is possible to obtain a photographed image with highresolution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a lens cross-sectional view illustrating a first configurationexample of an imaging lens according to an embodiment of the presentinvention and corresponding to Example 1;

FIG. 2 is a lens cross-sectional view illustrating a secondconfiguration example of an imaging lens according to an embodiment ofthe present invention and corresponding to Example 2;

FIG. 3 is a lens cross-sectional view illustrating a third configurationexample of an imaging lens according to an embodiment of the presentinvention and corresponding to Example 3;

FIG. 4 is a lens cross-sectional view illustrating a fourthconfiguration example of an imaging lens according to an embodiment ofthe present invention and corresponding to Example 4;

FIG. 5 is a lens cross-sectional view illustrating a fifth configurationexample of an imaging lens according to an embodiment of the presentinvention and corresponding to Example 5;

FIG. 6 is an aberration diagram illustrating various aberrations of animaging lens according to Example 1 of the present invention, whereSection A shows a spherical aberration, Section B shows astigmatism(curvature of field), Section C shows distortion, and Section D shows alateral chromatic aberration;

FIG. 7 is an aberration diagram illustrating various aberrations of animaging lens according to Example 2 of the present invention, whereSection A shows a spherical aberration, Section B shows astigmatism(curvature of field), Section C shows distortion, and Section D shows alateral chromatic aberration;

FIG. 8 is an aberration diagram illustrating various aberrations of animaging lens according to Example 3 of the present invention, whereSection A shows a spherical aberration, Section B shows astigmatism(curvature of field), Section C shows distortion, and Section D shows alateral chromatic aberration;

FIG. 9 is an aberration diagram illustrating various aberrations of animaging lens according to Example 4 of the present invention, whereSection A shows a spherical aberration, Section B shows astigmatism(curvature of field), Section C shows distortion, and Section D shows alateral chromatic aberration;

FIG. 10 is an aberration diagram illustrating various aberrations of animaging lens according to Example 5 of the present invention, whereSection A shows a spherical aberration, Section B shows astigmatism(curvature of field), Section C shows distortion, and Section D shows alateral chromatic aberration;

FIG. 11 is a diagram illustrating an imaging apparatus which is acellular phone terminal including the imaging lens according to thepresent invention; and

FIG. 12 is a diagram illustrating an imaging apparatus which is asmartphone including the imaging lens according to the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings.

FIG. 1 shows a first configuration example of an imaging lens accordingto a first embodiment of the present invention. The configurationexample corresponds to a lens configuration of a first numerical valueexample (Table 1 and Table 2) to be described later. Likewise, FIGS. 2to 5 show cross sections of second to fifth configuration examplescorresponding to the imaging lenses according to second to fifthembodiments to be described later. The second to fifth configurationexamples correspond to lens configurations of the second to fifthnumerical value examples (Tables 3 to 10) to be described later. InFIGS. 1 to 5, the reference sign Ri represents a radius of curvature ofi-th surface, where the number is the sequential number thatsequentially increases as it gets closer to an image side (an imagingside) when a surface of a lens element closest to an object side isregarded as a first surface. The reference sign Di represents an on-axissurface spacing between i-th surface and (i+1)th surface on an opticalaxis Z1. Since the respective configuration examples are basicallysimilar in configuration, the following description will be given on thebasis of the first configuration example of the imaging lens shown inFIG. 1, and the configuration examples shown in FIGS. 2 to 5 will bealso described as necessary. Further, FIGS. 1 to 5 also show the opticalpaths of on-axis rays 2 from the object point at an infinite distance,and rays 3 at the maximum angle of view.

An imaging lens L according to an embodiment of the present invention isappropriate to be used in various kinds of imaging apparatuses usingimaging devices such as a CCD and a CMOS. Especially, the imaging lens Lis appropriate to be used in relatively small-sized mobile terminalapparatus, for example, such as a digital still camera, a cellular phonewith a camera, a smartphone, a tablet terminal, and a PDA. This imaginglens L includes, along the optical axis Z1, a first lens L1, a secondlens L2, a third lens L3, a fourth lens L4, and a fifth lens L5 in thisorder from the object side.

FIG. 11 is a schematic diagram illustrating a cellular phone terminal,which is an imaging apparatus 1 according to an embodiment of thepresent invention. The imaging apparatus 1 according to the embodimentof the present invention includes imaging lens L according to thepresent embodiment and an imaging device 100 (refer to FIG. 1), such asa CCD, which outputs imaging signals based on an optical image formed bythe imaging lens L. The imaging device 100 is disposed at an imageformation surface (image plane R14) of the imaging lens L.

FIG. 12 is a schematic diagram illustrating a smartphone which is animaging apparatus 501 according to an embodiment of the presentinvention. The imaging apparatus 501 according to the embodiment of thepresent invention includes a camera unit 541 including the imaging lensL according to the present embodiment and the imaging device 100 (referto FIG. 1), such as a CCD, which outputs imaging signals based on anoptical image formed by the imaging lens L. The imaging device 100 isdisposed at the image formation surface (image plane R14) of the imaginglens L.

Various optical members CG may be disposed between the fifth lens L5 andthe imaging device 100 based on the configuration of a camera on whichthe imaging lens is mounted. For example, a fiat-plate-shaped opticalmember, such as a cover glass for protecting an imaging surface and aninfrared-ray cut filter, may be disposed. In this case, for example, aflat-plate-shaped cover glass to which a coating having an effect of afilter, such as an infrared-ray cut filter and an ND filter, has beenapplied, or a material having the same effect may be used as the opticalmember CG.

Alternatively, an effect similar to the optical member CG may be givento the fifth lens L5 or the like by applying a coating to the fifth lensL5 or the like without using the optical member CG. Thereby, it ispossible to reduce the number of components, and to reduce the totallength.

Further, it is desirable that the imaging lens L includes an aperturestop St disposed on the object side of an object side surface of thesecond lens L2. Since the aperture stop St is disposed on the objectside of the object side surface of the second lens L2 in such a manner,especially in a peripheral portion of an imaging area, it is possible toprevent an angle of incidence of rays, which pass through the opticalsystem and are incident onto an imaging surface (imaging device), frombecoming large. In order to further enhance this effect, it is moredesirable that the aperture stop St be disposed on the object side of anobject side surface of the first lens L1. Here, the expression “disposedon the object side of the object side surface of the second lens L2”means that the position of the aperture stop in the optical axisdirection is the same as an intersection point between an on-axismarginal ray and the object side surface of the second lens L2 orlocated on the object side of the intersection point. Likewise, theexpression “disposed on the object side of an object side surface of thefirst lens L1” means that the position of the aperture stop in theoptical axis direction is the same as an intersection point between anon-axis marginal ray and the object side surface of the first lens L1 orlocated on the object side of the intersection point.

Furthermore, when the aperture stop St is disposed on the object side ofthe object side surface of the first lens L1 in the optical axis, it isdesirable that the aperture stop St be disposed on the image side of avertex of the surface of the first lens L1. When the aperture stop St isdisposed on the image side of the vertex of the surface of the firstlens L1 in such a manner, it is possible to reduce the total length ofthe imaging lens including the aperture stop St. The imaging lensesaccording to the first to fifth embodiments (refer to FIGS. 1 to 5) areconfiguration examples in which the aperture stop St is disposed on theobject side of the object side surface of the first lens L1, and theaperture stop St is disposed on the image side of the vertex of thesurface of the first lens L1. However, the invention is not limited tothe embodiments, and the aperture stop St may be disposed on the objectside of the vertex of the surface of the first lens L. The arrangement,in which the aperture stop St is disposed on the object side of thevertex of the surface of the first lens L1, is slightly disadvantageousin terms of securing a peripheral light amount, compared with a casewhere the aperture stop St is disposed on the image side of the vertexof the surface of the first lens L1. However, the arrangement canprevent an angle of incidence of rays, which pass through the opticalsystem and are incident onto the imaging surface (imaging device), frombecoming large in the peripheral portion of the imaging area in a moredesirable manner. It should be noted that the aperture stop St shownherein does not necessarily represent the size or shape thereof butshows the position thereof on the optical axis Z1.

In the imaging lens L, the first lens L1 has a positive refractive powerin the vicinity of the optical axis, and has a meniscus shape which isconcave toward the image side in the vicinity of the optical axis. Byforming the first lens L1 in a meniscus shape which is concave towardthe image side in the vicinity of the optical axis, the position of therear side principal point of the first lens L1 can be set to be close tothe object side, and thus it is possible to appropriately reduce thetotal length. Further, as shown in the first to fifth embodiments, byforming the first lens L1 in an aspheric shape, it is possible toappropriately correct a spherical aberration.

The second lens L2 has a negative refractive power in the vicinity ofthe optical axis. Hence, it is possible to satisfactorily correct aspherical aberration and a longitudinal chromatic aberration which arecaused when the rays pass through the first lens L1. Further, as shownin the first to fifth embodiments, it is desirable that the second lensL2 be concave toward the image side in the vicinity of the optical axis.In this case, it is possible to appropriately reduce the total length.Furthermore, as shown in the first to third embodiments, the second lensL2 may have a biconcave shape in the vicinity of the optical axis, andas shown in the fourth and fifth embodiments, the second lens L2 mayhave a meniscus shape which is concave toward the image side in thevicinity of the optical axis. When the second lens L2 is formed in themeniscus shape which is concave toward the image side in the vicinity ofthe optical axis, the position of the rear side principal point of thesecond lens L2 can be set to be close to the object side, and thus it ispossible to more appropriately reduce the total length.

The third lens L3 has a negative refractive power in the vicinity of theoptical axis. Further, as shown in the first embodiment, the third lensL3 may have a biconcave shape in the vicinity of the optical axis, asshown in the second and fourth embodiments, the third lens L3 may have ameniscus shape which is concave toward the image side in the vicinity ofthe optical axis, and as shown in the third and fifth embodiments, thethird lens L3 may have a meniscus shape which is convex toward the imageside in the vicinity of the optical axis. When the third lens L3 has ameniscus shape which is concave toward the image side in the vicinity ofthe optical axis, the position of the rear side principal point of thethird lens L3 can be more appropriately set to be close to the objectside, and thus it is possible to appropriately reduce the total length.

Further, it is desirable that an absolute value |f3| of the focal lengthof the third lens L3 be set to the maximum among absolute values |f1| to|f5| of the focal lengths of the first to fifth lenses L1 to L5. In thiscase, it is possible to more appropriately reduce an effect of change ina shape of the surface of the third lens L3 on the focal length f of thewhole system, and thus the third lens L3 can be flexibly designed tohave a shape of the surface appropriate for correcting variousaberrations.

Further, as shown in the first to fifth embodiments, it is desirablethat the image side surface of the third lens L3 have an aspheric shape,an intersection point between the image side surface of the third lensL3 and a principal ray with a maximum angle of view be positioned on theobject side of an intersection point between the image side surface ofthe third lens L3 and an optical axis, and an intersection point betweenan object side surface of the third lens L3 and the principal ray withthe maximum angle of view be positioned on the object side of anintersection point between the object side surface of the third lens L3and the optical axis. In this case, it is possible to appropriatelycorrect a spherical aberration and astigmatism, and it is possible toachieve high resolution performance in the range from the central angleof view to the peripheral angle of view.

Further, as shown in the first, second, and fourth embodiments, when thethird lens L3 is formed to be concave toward the image side in thevicinity of the optical axis, by making the image side surface of thethird lens L3 have an aspheric shape which has at least one extremepoint, the intersection point between the image side surface of thethird lens L3 and the principal ray with the maximum angle of view canbe positioned on the object side of the intersection point between theimage side surface of the third lens L3 and the optical axis, and theextreme point of the image side surface of the third lens L3 can bedisposed at an arbitrary position on the inside of the intersectionpoint between the image side surface of the third lens L3 and theprincipal ray with the maximum angle of view in a radial direction ofthe third lens L3.

Further, as shown in the second and fourth embodiments, when the thirdlens L3 is formed to be convex toward the object side in the vicinity ofthe optical axis, by making the object side surface of the third lens L3have an aspheric shape which has at least one extreme point, theintersection point between the object side surface of the third lens L3and the principal ray with the maximum angle of view can be positionedon the object side of the intersection point between the object sidesurface of the third lens L3 and the optical axis, and the extreme pointof the object side surface of the third lens L3 can be disposed at anarbitrary position on the inside of the intersection point between theobject side surface of the third lens L3 and the principal ray with themaximum angle of view in the radial direction of the third lens L3.

In the imaging lens, the first lens L1 has a positive refractive powerin the vicinity of the optical axis, and the second lens L2 and thethird lens L3 have negative refractive powers in the vicinity of theoptical axis. Hence, the lens group formed of the first to third lensesL1 to L3 (hereinafter referred to as a first lens group) can be made tohave a telephoto type configuration. In the configuration, the firstlens L1 having the positive refractive power is disposed on the objectside, and the second lens L2 and the third lens L3 having the negativerefractive powers are disposed on the image side. Hence, the position ofthe rear side principal point of the first lens group, which is formedof the first to third lenses L1 to L3, can be set to be close to theobject side, and thus it is possible to appropriately reduce the totallength.

The fourth lens L4 has a positive refractive power in the vicinity ofthe optical axis. Further, as shown in the first to fourth embodiments,it is desirable that the fourth lens L4 has a meniscus shape which isconvex toward the image side in the vicinity of the optical axis.Thereby, it is possible to decrease an angle of incidence at which lightis incident onto the object side surface of the fourth lens L4, comparedwith a case where the fourth lens L4 is concave toward the image side inthe vicinity of the optical axis, and it is possible to suppressoccurrence of various aberrations. Hence, it is possible toappropriately correct distortion (a distortion aberration), a lateralchromatic aberration, and astigmatism which tend to be caused byreduction in the total length.

The fifth lens L5 has a negative refractive power in the vicinity of theoptical axis. As described above, by making the fourth lens L4 have apositive refractive power in the vicinity of the optical axis and makingthe fifth lens L5 have a negative refractive power in the vicinity ofthe optical axis, the lens group formed of the fourth lens L4 and thefifth lens L5 (hereinafter referred to as a second lens group) can bemade to have a telephoto type configuration. Hence, the position of therear side principal point of the second lens group can be set to beclose to the object side, and thus it is possible to appropriatelyreduce the total length.

Further, the image side surface and object side surface of the fifthlens L5 are formed to be aspheric. As shown in the first to fifthembodiments, it is desirable that the fifth lens L5 has an asphericshape which is concave toward the image side in the vicinity of theoptical axis and has at least one extreme point on the image sidesurface. Thereby, it is possible to satisfactorily correct a curvatureof field and achieve high resolution performance in the range from thecentral angle of view to the peripheral angle of view while suppressingoccurrence of distortion in the positive direction. The extreme point ofthe image side surface of the fifth lens L5 can be disposed at anarbitrary position on the inside of the intersection point between theimage side surface of the fifth lens L5 and the principal ray with themaximum angle of view in the radial direction of the fifth lens L5.

It should be noted that, in the present description, the “extreme point”means a point at which a function fx (r) is at a maximum value or aminimum value when a point on the lens surface is represented by (r, fx(r)). Here, the distance from the optical axis in a directionperpendicular to the optical axis is r (r>0), and a functionrepresenting the position at the distance r in the optical axisdirection is fx(r). All the extreme points of the respective embodimentsof the present description are extreme points at which the tangent planeis perpendicular to the optical axis.

Further, by making the fifth lens L5 concave toward the image side andmaking the image side surface of the fifth lens L5 have an asphericshape which has at least one extreme point, especially in the peripheralportion of the imaging area, it is possible to prevent the angle ofincidence of rays, which pass through the optical system and areincident onto the imaging surface (imaging device), from becoming large.It should be noted that the peripheral portion of the imaging areadescribed herein means the outside of about 50% of the height in theradial direction. Here, the height is a height of the intersection pointbetween the principal ray with the maximum angle of view and the surfacefrom the optical axis.

Moreover, it is desirable that the fifth lens L5 have a meniscus shapewhich is convex toward the object side in the vicinity of the opticalaxis, and each of the object side surface and the image side surfacethereof has an aspheric shape which has at least one extreme point.Thereby, it is possible to set the position of the rear side principalpoint of the fifth lens L5 to be close to the object side, and thusappropriately reduce the total length, while preventing the angle ofincidence of rays, which pass through the optical system and areincident onto the imaging surface (imaging device), from becoming large,especially in the peripheral portion of the imaging area.

According to the imaging lens L, in the imaging lens which is composedof five lenses as a whole, a configuration of each lens element of thefirst to fifth lenses L1 to L5 is optimized. Therefore, it is possibleto achieve a lens system that has high resolution performance whiledecreasing the total length thereof.

In the imaging lens L, in order to enhance the performance thereof, itis desirable that at least one surface of each lens of the first tofifth lenses L1 to L5 be formed as an aspheric surface.

Further, it is desirable that each of the lenses L1 to L5 constitutingthe imaging lens L be not formed as a cemented lens but a single lens.The reason is that, compared with a case where any of the lenses L1 toL5 is formed as a cemented lens, since the number of aspheric surfacesincreases, a degree of freedom in design of each lens is enhanced, andit is possible to appropriately achieve reduction in the total lengththereof.

Further, for example, as in the imaging lenses according to the first tofifth embodiments, when each lens configuration of the first to fifthlenses L1 to L5 of the imaging lens L is set such that the total angleof view is equal to or greater than 60 degrees, the imaging lens L canbe appropriately applied to a cellular phone terminal and the like whichare often used in a close-up shot.

Next, effects and advantages of the conditional expressions of theimaging lens L configured as described above will be described indetail.

First, a focal length f of the whole system and a composite focal lengthf45 of the fourth and fifth lenses L4 and L5 satisfy the followingconditional expression (1).

0.043<f/f45<0.186  (1)

The conditional expression (1) defines a desirable numerical range of aratio of the focal length f of the whole system to the composite focallength f45 of the fourth and fifth lenses L4 and L5. By maintaining thepositive composite refractive power of the fourth and fifth lenses L4and L5 such that the f/f45 is greater than the lower limit of theconditional expression (1), especially at the medium angle of view, itis possible to more appropriately prevent the angle of incidence ofrays, which pass through the optical system and are incident onto theimaging surface (imaging device), from becoming large. In addition, itis possible to appropriately correct distortion (a distortionaberration) and a lateral chromatic aberration. Further, it isadvantageous in reducing the total length to maintain the positivecomposite refractive power of the fourth and fifth lenses L4 and L5 suchthat the f/f45 is less than the upper limit of the conditionalexpression (1). In order to further enhance the effect, it is desirableto satisfy the conditional expression (1-1), and it is more desirable tosatisfy the conditional expression (1-2).

0.053<f/f45<0.178  (1-1)

0.063<f/f45<0.17  (1-2)

The focal length f of the whole system and a focal length f4 of thefourth lens L4 satisfy the following conditional expression (2).

0.961<f/f4<1.785  (2)

The conditional expression (2) defines a desirable numerical range of aratio of the focal length f of the whole system to the focal length f4of the fourth lens L4. By securing the positive refractive power of thefourth lens L4 such that the f/f4 is greater than the lower limit of theconditional expression (2), the positive refractive power of the fourthlens L4 becomes not excessively weak relative to the refractive power ofthe whole system, and thus, especially at the medium angle of view, itis possible to more appropriately prevent the angle of incidence ofrays, which pass through the optical system and are incident onto theimaging surface (imaging device), from becoming large. In addition, itis possible to appropriately correct distortion (a distortionaberration) and a lateral chromatic aberration. By maintaining thepositive refractive power of the fourth lens L4 such that the f/f4 isless than the upper limit of the conditional expression (2), thepositive refractive power of the fourth lens L4 becomes not excessivelystrong relative to the refractive power of the whole system, and thus itis possible to appropriately correct a spherical aberration andastigmatism. In order to further enhance the effect, it is desirable tosatisfy the conditional expression (2-1), and it is more desirable tosatisfy the conditional expression (2-2).

1<f/f4<1.681  (2-1)

1<f/f4<1.58  (2-2)

As described above, according to the imaging lens of the embodiment ofthe present invention, in the imaging lens which is composed of fivelenses as a whole, the configuration of each lens element is optimized.Therefore, it is possible to achieve a lens system that has highresolution performance while decreasing the total length thereof.

As in the above-mentioned imaging lens, the lens system disclosed inPatent Document 1 or Patent Document 2 also substantially consisting of,in order from the object side: a first lens having a positive refractivepower; a second lens having a negative refractive power; a third lenshaving a negative refractive power; a fourth lens having a positiverefractive power; and a fifth lens having a negative refractive power,and the lens system is composed of a telephoto-type first lens groupincluding the first to third lenses and a telephoto-type second lensgroup including the fourth lens and the fifth lens. However, in the lenssystem disclosed in Patent Document 1 or Patent Document 2, the negativerefractive power of the fifth lens is excessively strong, and thus inorder to achieve balance in the refractive power, the refractive powerof the fourth lens is made to be strong by securing the center thicknessof the fourth lens. For this reason, the on-axis length of the secondlens group composed of the fourth lens and the fifth lens is notsufficiently reduced. For example, assuming that the distance on theoptical axis from the object side surface of the first lens to the imageplane (the total length of the imaging lens) is L and the focal lengthof the whole system is f, the ratio L/f is about 1.24 in Patent Document1, and is about 1.17 to 1.26 in Patent Document 2.

In contrast, according to the imaging lens L, as shown in theconditional expressions (1) and (2), the refractive power of the secondlens group composed of the fourth lens L4 and the fifth lens L5 and therefractive power of the fourth lens L4 are appropriately set not tobecome excessively strong relative to the refractive power of the wholelens. Hence, in order to secure the refractive power of the fourth lensL4, it is not necessary to increase the center thickness of the fourthlens L4, and it is possible to reduce the length of the second lensgroup in the optical axis direction. As a result, it is possible to moreappropriately achieve reduction in the total length. For example, in thefirst to fifth embodiments, above-mentioned L/f is about 1.12 to 1.15.

By satisfying appropriately desirable conditions, it is possible toachieve higher imaging performance. Furthermore, according to theimaging apparatus of the embodiment, imaging signals based on an opticalimage, which is formed by the high-performance imaging lens according tothe embodiment, are output. Therefore, it is possible to obtain aphotographed image with high resolution in the range from the centralangle of view to the peripheral angle of view.

Next, specific numerical examples of the imaging lens according to theembodiment of the present invention will be described. Hereinafter, aplurality of numerical examples will be described collectively.

Table 1 and Table 2, which will be given later, show specific lens datacorresponding to the configuration of the imaging lens shown in FIG. 1.Specifically, Table 1 shows basic lens data, and Table 2 shows data onaspheric surfaces. In the lens data shown in Table 1, the column ofsurface number Si shows the surface number of the i-th surface in theimaging lens of Example 1. The surface of the lens element closest tothe object side is the first surface (the aperture stop St is thefirst), and surface numbers sequentially increase toward the image side.The column of the radius of curvature Ri shows values (m) of the radiusof curvature of i-th surface from the object side to correspond to thereference sign Ri in FIG. 1. Likewise, the column of the on-axis surfacespacing Di shows spaces (mm) on the optical axis between the i-thsurface Si and the (i+1) th surface Si+1 on the optical axis from theobject side. The column of Ndj shows values of the refractive index ofthe j-th optical element from the object side for the d-line (587.56nm). The column of vdj shows values of the Abbe number of the j-thoptical element from the object side for the d-line.

In the imaging lens according to Example 1, both surfaces of each of thefirst to fifth lenses L1 to L5 are aspheric. In the basic lens datashown in Table 1, the radii of curvature of these aspheric surfaces arerepresented as numerical values of the radius of curvature near theoptical axis (paraxial radius of curvature).

Table 2 shows aspheric surface data in the imaging lens system accordingto Example 1. In the numerical values represented as the asphericsurface data, the reference sign “E” means that a numerical valuefollowing this is a “exponent” having a base of 10 and that thisnumerical value having a base of 10 and expressed by an exponentialfunction is multiplied by a numerical value before the “E”. For example,this means that “1.0E−02” is “1.0×10⁻²”.

As aspheric surface data, values of coefficients Ai and KA in theaspheric surface expression represented by the following expression (A)are shown. Specifically, Z represents the length (mm) of a perpendicularfrom a point on an aspheric surface at height h from an optical axis toa plane that contacts with the vertex of the aspheric surface (the planeperpendicular to the optical axis).

Z=C·h ²/{1+(1−KA·C ² ·h ²)^(1/2) }ΣAi·h ^(i)  (A)

Here,

Z is a depth of the aspheric surface (mm),

h is a distance (height) from the optical axis to the lens surface (mm),

C is a paraxial curvature=1/R

(R: a paraxial radius of curvature),

Ai is an i-th order aspheric surface coefficient (i is an integer equalto or greater than 3), and

KA is an aspheric surface coefficient.

In a similar manner to the imaging lens according to the above-mentionedExample 1, Tables 3 to 10 show specific lens data as Examples 2 to 5,corresponding to the configuration of the imaging lenses shown in FIGS.2 to 5. In the imaging lenses according to Examples 1 to 5, bothsurfaces of each of the first to fifth lenses L1 to L5 are aspheric.

FIG. 6, Section A to Section D show a spherical aberration, astigmatism(curvature of field), distortion (a distortion aberration), and alateral chromatic aberration (a chromatic aberration of magnification)in the imaging lens of Example 1, respectively. Each aberration diagramillustrating a spherical aberration, astigmatism (curvature of field),and distortion (a distortion aberration) shows an aberration for thed-line (a wavelength of 587.56 nm) as a reference wavelength. Thediagram of a spherical aberration diagram and the diagram of a lateralchromatic aberration diagram show also aberrations for the F-line (awavelength of 486.1 nm) and the C-line (a wavelength of 656.27 nm). Thediagram of a spherical aberration also shows an aberration for theg-line (a wavelength of 435.83 nm). In the diagram of astigmatism, thesolid line indicates an aberration in the sagittal direction (S), andthe broken line indicates an aberration in the tangential direction (T).Fno. indicates an F-number, and ω indicates a half angle of view.

Likewise, FIG. 6, Section A to D to FIG. 10, Section A to D show variousaberrations of the imaging lenses of Examples 2 to 5.

Table 11 collectively shows values of the conditional expressions (1)and (2) of Examples 1 to 5 according to the present invention. In Table11, Fho. is an F-number, f is the focal length of the whole system, Bfis a distance on the optical axis from the image side surface of thelens closest to the image side to the image plane (Bf corresponds to aback focal length), L is a distance on the optical axis from the objectside surface of the first lens L1 to the image plane, and 2ω is a totalangle of view. Bf is an air conversion length, that is, indicates avalue which is calculated by air-converting the thickness of an opticalmember PP. Likewise, the back focal length portion of L uses an airconversion length. As can be seen from Table 11, all Examples 1 to 5satisfy the conditional expressions (1) and (2).

It should be noted that the respective tables show numerical valueswhich are rounded off to a predetermined decimal place. Regarding unitsof the numerical values, “°” is used for an angle, and “mm” is used fora length. However, those are just examples, and other appropriate unitsmay be used since the optical system has the same optical performanceeven when being scaled up or scaled down.

As can be seen from the above-mentioned numerical value data andaberration diagrams, in each example, high imaging performance isachieved while the total length is reduced.

The imaging lens of the present invention is not limited to theabove-mentioned embodiments and examples, and may be modified to variousforms. For example, the values of the radius of curvature, the on-axissurface spacing, the refractive index, the Abbe number, the asphericsurface coefficient, and the like of the lens elements are not limitedto the values shown in the numerical examples, and may have differentvalues.

Further, in the description of each of all the examples, it is a premisethat the imaging lens is used with fixed focus, but it may be possibleto adopt a configuration in which focus is adjustable. For example, theimaging lens may be configured in such a manner that autofocusing ispossible by extending the whole lens system or by moving some lenses onthe optical axis. Further, the imaging lens of the present invention maybe configured such that, in each lens which is formed in a meniscusshape in the vicinity of the optical axis, a surface with a largeabsolute value of the radius of curvature of the meniscus shape in thevicinity of the optical axis is set to be planar. In other words, thelens, which is formed in a meniscus shape in the vicinity of the opticalaxis, may be a piano-convex lens or a plano-concave lens of which asurface with a large absolute value of the radius of curvature of themeniscus shape is planar.

TABLE 1 EXAMPLE 1 Si Ri Di Ndj νdj 1(APERTURE ∞ −0.209 STOP) *2 1.484580.729 1.54488 54.87 *3 48.10428 0.047 *4 −64.41218 0.274 1.63351 23.63*5 3.69094 0.471 *6 −24.27338 −0.276 1.63351 23.63 *7 47.41660 0.299 *8−2.81487 −0.684 1.54488 54.87 *9 −1.03504 0.290 *10 3.64149 0.3041.54488 54.87 *11 0.98422 0.543 12 ∞ 0.300 1.56700 37.80 13 ∞ 0.626 14 ∞*ASPHERIC SURFACE

TABLE 2 EXAMPLE 1 • ASPHERIC SURFACE DATA SURFACE NUMBER KA A3 A4 A5 A62 8.8124980E−01 0.0000000E+00 1.6120555E−01 −3.4247252E+00 3.4939443E+013 2.5799991E+03 0.0000000E+00 −2.8047928E−01 7.5206537E−01−3.2833868E+00 4 −1.3888236E+05 0.0000000E+00 −4.1865352E−014.1951395E−01 9.7274999E+00 5 2.5653380E+00 0.0000000E+00 −1.2363340E−015.9979706E−01 −1.4563107E+00 6 −1.0075113E+04 0.0000000E+00−2.2844306E−01 −1.5936468E+00 6.0392562E+00 7 1.8871624E+030.0000000E+00 −5.9223797E−01 3.8173389E+00 −2.5793482E+01 8−8.8864496E+00 0.0000000E+00 −2.1820328E−01 1.2259799E+00 −7.6445376E+009 −1.8385916E+00 0.0000000E+00 −1.0367156E−01 −3.8272072E−014.3824783E+00 10 −2.1672884E+02 0.0000000E+00 −3.2716685E−02−9.6299117E−01 3.4373818E+00 11 −2.9882304E+00 0.0000000E+00−7.6430017E−01 1.5403521E+00 −2.1651330E+00 A7 A8 A9 A10 A11 2−2.2421599E+02 9.8692485E+02 −3.0962040E+03 7.0764451E+03 −1.1895677E+043 9.3152155E+00 −9.6317599E+00 −4.3795223E+00 1.2799195E+01−3.1484007E+00 4 −9.0055607E+01 4.4143098E+02 −1.4139428E+033.2058203E+03 −5.3236802E+03 5 5.7286609E−01 7.5525041E+00−1.5600780E+01 7.3804765E+00 9.2327559E−01 6 −6.2946097E+00−9.0264485E+00 2.3155973E+01 −7.3457128E+00 −9.5517302E+00 71.1916116E+02 −3.9342858E+02 9.4982573E+02 −1.6905313E+03 2.2102143E+038 3.1966365E+01 −9.3131519E+01 1.9619393E+02 −3.0446049E+023.4847168E+02 9 −1.8533663E+01 4.8225684E+01 −8.7567982E+011.1651567E+02 −1.1462238E+02 10 −7.9818724E+00 1.4357004E+01−1.9322510E+01 1.8942989E+01 −1.3378663E+01 11 3.2738924E+00−4.9850162E+00 6.0674281E+00 −5.3967078E+00 3.4438471E+00 A12 A13 A14A15 A16 2 1.4624009E+04 −1.2810093E+04 7.5615554E+03 −2.6870209E+034.3258126E+02 3 1.4189329E+01 −5.4264275E+01 6.2024516E+01−2.8234676E+01 4.0456217E+00 4 6.4837531E+03 −5.6367603E+033.2960088E+03 −1.1542317E+03 1.8184868E+02 5 1.1732157E+01−1.5225632E+01 −3.1646703E+00 9.6000610E+00 −2.6030029E+00 6−1.2136087E+01 3.3896499E+01 −2.0532517E+01 3.7801905E+00 −2.4865728E−017 −2.0922914E+03 1.3922602E+03 −6.1626572E+02 1.6281445E+02−1.9488163E+01 8 −2.9104017E+02 1.7326160E+02 −7.0009391E+011.7263580E+01 −1.9631318E+00 9 8.2166369E+01 −4.1539857E+011.3970668E+01 −2.7893288E+00 2.4796822E−01 10 6.7106392E+00−2.3250421E+00 5.2826853E−01 −7.0916967E−02 4.2838647E−03 11−1.5622354E+00 4.9289979E−01 −1.0300683E−01 1.2828603E−02 −7.2028051E−04

TABLE 3 EXAMPLE 2 Si Ri Di Ndj νdj 1(APERTURE ∞ −0.209 STOP) *2 1.499640.729 1.54488 54.87 *3 310.32948 0.047 *4 −81.46652 0.274 1.63351 23.63*5 3.35594 0.471 *6 56.29833 0.276 1.63351 23.63 *7 42.11341 0.299 *8−2.37040 0.684 1.54488 54.87 *9 −1.01264 0.290 *10 3.90127 0.304 1.5448854.87 *11 1.00474 0.543 12 ∞ 0.300 1.56700 37.80 13 ∞ 0.607 14 ∞*ASPHERIC SURFACE

TABLE 4 EXAMPLE 2 • ASPHERIC SURFACE DATA SURFACE NUMBER KA A3 A4 A5 A62 1.3129764E+00 0.0000000E+00 1.5728582E−01 −3.5535908E+00 3.5389179E+013 5.7217543E+01 0.0000000E+00 −2.3280001E−01 6.5518674E−01−3.2747662E+00 4 −3.4292285E+05 0.0000000E+00 −3.6022466E−011.7951952E−01 1.0110644E+01 5 2.1418607E+00 0.0000000E+00 −1.7611657E−018.7348369E−01 −2.0289642E+00 6 −1.0613004E+06 0.0000000E+001.2742597E−01 −2.8721825E+00 8.0221825E+00 7 1.4586676E+03 0.0000000E+00−5.9690952E−01 3.8772475E+00 −2.5898620E+01 8 −6.8343979E+000.0000000E+00 −2.1338990E−01 1.1104382E+00 −7.4920042E+00 9−2.8236329E+00 0.0000000E+00 −2.5395195E−01 −2.2769122E−01 4.3438041E+0010 −1.9422967E+02 0.0000000E+00 −1.6213631E−02 −9.6200568E−013.4237713E+00 11 −2.7335684E+00 0.0000000E+00 −7.7531438E−011.5806248E+00 −2.1780908E+00 A7 A8 A9 A10 A11 2 −2.2498221E+029.8742311E+02 −3.0960024E+03 7.0761139E+03 −1.1895850E+04 39.5137241E+00 −9.6537212E+00 −4.7539571E+00 1.2989906E+01 −3.0855493E+004 −9.0265083E+01 4.4140574E+02 −1.4139377E+03 3.2057863E+03−5.3237595E+03 5 8.4261696E−01 7.8761202E+00 −1.5538389E+016.9735035E+00 7.9325292E−01 6 −7.2419078E+00 −9.4139201E+002.2896955E+01 −6.8732157E+00 −8.9783537E+00 7 1.1924688E+02−3.9343827E+02 9.4995413E+02 −1.6905962E+03 2.2102096E+03 83.1990427E+01 −9.3160120E−01 1.9616729E+02 −3.0447022E+02 3.4848318E+029 −1.8531383E+01 4.8228873E+01 −8.7567178E+01 1.1651154E+02−1.1462435E+02 10 −7.9811429E+00 1.4358474E+01 −1.9321894E+011.8943004E+01 −1.3378662E+01 11 3.2752306E+00 −4.9840904E+006.0674406E+00 −5.3967427E+00 3.4438122E+00 A12 A13 A14 A15 A16 21.4624082E+04 −1.2809734E+04 7.5616625E+03 −2.6876163E+03 4.3285980E+023 1.4358435E+01 −5.4357910E+01 6.1800915E+01 −2.8112785E+014.0748326E+00 4 6.4841857E+03 −5.6366159E+03 3.2956462E+03−1.1544658E+03 1.8210277E+02 5 1.1649615E+01 −1.5103356E+01−2.7506331E+00 9.7355962E+00 −2.9971292E+00 6 −1.2247297E+013.3433294E+01 −2.0858205E+01 3.6346552E+00 1.2484219E−01 7−2.0922848E+03 1.3922805E+03 −6.1625690E+02 1.6280967E+02 −1.9493721E+018 −2.9103932E+02 1.7326288E+02 −7.0010154E+01 1.7262422E+01−1.9620546E+00 9 8.2167043E+01 −4.1539229E+01 1.3970621E+01−2.7890318E+00 2.4784094E−01 10 6.7106528E+00 −2.3250747E+005.2825776E−01 −7.0916066E−02 4.2860086E−03 11 −1.5622311E+004.9289971E−01 −1.0300558E−01 1.2828874E−02 −7.2045864E−04

TABLE 5 EXAMPLE 3 Si Ri Di Ndj νdj 1(APERTURE ∞ −0.209 STOP) *2 1.499240.729 1.54488 54.87 *3 44.97305 0.047 *4 −216.91378 0.274 1.63351 23.63*5 3.53302 0.471 *6 −48.10428 0.276 1.63351 23.63 *7 −271.51584 0.299 *8−2.39086 0.684 1.54488 54.87 *9 −1.01809 0.290 *10 3.31249 0.304 1.5448854.87 *11 0.96367 0.543 12 ∞ 0.300 1.56700 37.80 13 ∞ 0.617 14 ∞*ASPHERIC SURFACE

TABLE 6 EXAMPLE 3 • ASPHERIC SURFACE DATA SURFACE NUMBER KA A3 A4 A5 A62 8.2599974E−01 0.0000000E+00 1.6975702E−01 −3.4568182E+00 3.4963983E+013 −2.9822507E−01 0.0000000E+00 −2.7612836E−01 7.8275572E−01−3.3572956E+00 4 −6.9537536E+05 0.0000000E+00 −3.6192238E−012.7395534E−01 9.8145007E+00 5 3.4124434E+00 0.0000000E+00 −1.3386778E−016.2938558E−01 −1.5404832E+00 6 −7.2675065E+04 0.0000000E+00−1.8550699E−01 −1.7142452E+00 6.2502394E+00 7 5.4291390E+040.0000000E+00 −5.8500910E−01 3.8695423E+00 −2.5854465E+01 8−9.9192329E+00 0.0000000E+00 −2.7151541E−01 1.2467215E+00 −7.5985165E+009 −2.0963521E+00 0.0000000E+00 −1.6552275E−01 −3.2723556E−014.3763671E+00 10 −1.6554403E+02 0.0000000E+00 −2.6534069E−02−9.7112910E−01 3.4385382E+00 11 −2.9671741E+00 0.0000000E−00−7.5895143−01 1.5349396E+00 −2.1648265E+00 A7 A8 A9 A10 A11 2−2.2406590E+02 9.8658816E+02 −3.0960306E+03 7.0764960E+03 −1.1895652E+043 9.3164431E+00 −9.5600572E+00 −4.3642377E+00 1.2854142E+01−3.2695222E+00 4 −9.0016588E+01 4.4140686E+02 −1.4139943E+033.2058395E+03 −5.3235076E+03 5 5.9519032E−01 7.6268269E+00−1.5582805E+01 7.3158321E+00 8.5197641E−01 6 −6.4784653E+00−9.0355034E+00 2.3112421E+01 −7.2922921E+00 −9.3920646E+00 71.1918639E+02 −3.9340576E+02 9.4989433E+02 −1.6905102E+03 2.2102205E+038 3.1975327E+01 −9.3140727E+01 1.9618493E+02 −3.0446342E+023.4847195E+02 9 −1.8529775E+01 4.8222737E+01 −8.7567528E+011.1651549E+02 −1.1462268E+02 10 −7.9815220E+00 1.4356969E−01−1.9322412E+01 1.8943052E+01 −1.3378678E+01 11 3.2747286E+00−4.9850633E+00 6.0673936E+00 −5.3967148E+00 3.4438418E+00 A12 A13 A14A15 A15 2 1.4624039E+04 −1.2810299E+04 7.5616519E+03 −2.6869669E+034.3254709E+02 3 1.4135173E+01 −5.4250975E+01 8.2033902E+01−2.8124757E+01 3.9954263E+00 4 6.4837298E+03 −5.6368455E+033.2960219E+03 −1.1542470E+03 1.8189582E+02 5 1.1733147E+01−1.5184739E−01 −3.1023904E+00 9.6445005E+00 −2.7149000E+00 6−1.2162638E+01 3.3655686E+01 −2.0678878E+01 3.6534359E+00 −3.1753649E−027 −2.0923003E+03 1.3922492E+03 −6.1627112E+02 1.6282041E+02−1.9478643E+01 8 −2.9104642E+02 1.7326536E+02 −7.0008965E+011.7264502E+01 −1.9630069E+00 9 8.2166081E+01 −4.1540071E+011.3970502E+01 −2.7892707E+00 2.4812075E−01 10 6.7106434E+00−2.3250465E+00 5.2828685E−01 −7.0917195E−02 4.2841580E−03 11−1.5622375E+00 4.9290048E−01 −1.0300550E−01 1.2828635E−02 −7.2040747E−04

TABLE 7 EXAMPLE 4 Si Ri Di Ndj νdj 1(APERTURE ∞ −0.209 STOP) *2 1.486750.729 1.54488 54.87 *3 87.66769 0.047 *4 53.82357 0.274 1.63351 23.63 *52.98226 0.471 *6 58.91021 0.276 1.63351 23.63 *7 47.61879 0.299 *8−2.39204 0.684 1.54488 54.87 *9 −1.02021 0.290 *10 3.68727 0.304 1.5448854.87 *11 0.99700 0.543 12 ∞ 0.300 1.56700 37.80 13 ∞ 0.601 14 ∞*ASPHERIC SURFACE

TABLE 8 EXAMPLE 4 • ASPHERIC SURFACE DATA SURFACE NUMBER KA A3 A4 A5 A62 4.4010493E−01 0.0000000E+00 2.0080627E−01 −3.5642329E+00 3.5299377E+013 −7.7866874E+05 0.0000000E+00 −2.7414627E−01 7.5337525E−01−3.3576902E+00 4 −5.5636774E+04 0.0000000E+00 −3.5530066E−011.6114451E−01 1.0137294E+01 5 1.6632055E+00 0.0000000E+00 −1.6609856E−017.2186801E−01 −1.6632997E+00 6 −1.9195519E+06 0.0000000E+004.9189188E−02 −2.6281950E+00 7.6915478E+00 7 1.8740449E+03 0.0000000E+00−6.3037077E−01 3.9228394E+00 −2.5939196E+01 8 −8.0032266E+000.0000000E+00 −2.5431502E−01 1.1759158E+00 −7.5553660E+00 9−2.5547952E+00 0.0000000E+00 −2.2826103E−01 −2.5575673E−01 4.3443435E+0010 −1.8763009E+02 0.0000000E+00 −2.8106553E+02 −9.5008732E−01−3.4227311E+00 11 −2.8809972E+00 0.0000000E+00 −7.6415695E−011.5417522E+00 −2.1669865E+00 A7 A8 A9 A10 A11 2 −2.2471798E+029.8737346E+02 −3.0964355E+03 7.0763310E+03 −1.1895438E+04 39.4289011E+00 −9.1786025E+00 −5.5071073E+00 1.3320977E+01 −2.7026510E+004 −9.0226128E+01 4.4133990E+02 −1.4139389E+03 3.2058150E+03−5.3237475E−03 5 7.1623764E−01 7.6185407E+00 −1.5570923E+017.1023365E+00 1.0088877E+00 6 −7.1672191E+00 −9.2905762E+002.3044013E+01 −7.0887467E+00 −9.0783728E+00 7 1.1924359E+02−3.9339312E+02 9.4990202E+02 −1.6905522E+03 2.2102057E+03 83.1987316E+01 −9.3132747E+01 1.9617190E+02 −3.0446269E+02 3.4848470E+029 −1.8527021E+01 4.8228644E+01 −8.7566104E+01 1.1651114E+02−1.1462444E+02 10 −7.9846592E+00 1.4359408E+01 −1.9321825E+011.8943168E+01 −1.3378638E+01 11 3.2732794E+00 −4.9844558E+006.0673022E+00 −5.3966345E+00 3.4438366E+00 A12 A13 A14 A15 A16 21.4624070E+04 −1.2810311E+04 7.5616526E+03 −2.6870873E+03 4.3262558E+023 1.3752051E+01 −5.4047752E+01 6.1969458E+01 −2.8397533E+014.1577380E+00 4 6.4841267E+03 −5.6367245E+03 3.2959670E+03−1.1546657E+03 1.8203305E+02 5 1.1866860E+01 −1.5245532E+01−3.1146467E+00 9.4068596E+00 −2.4831725E+00 6 −1.2231148E+013.3537006E+01 −2.0793656E+01 3.5956174E+00 8.8572704E−02 7−2.0923124E+03 1.3922735E+03 −6.1624459E+02 1.6283223E+02 −1.9510094E+018 −2.9105808E+02 1.7326160E+02 −7.0005268E+01 1.7265682E+01−1.9638073E+00 9 8.2166493E+01 −4.1539142E+01 1.3971101E+01−2.7892772E+00 2.4785368E−01 10 6.7106159E+00 −2.3250809E+005.2825211E−01 −7.0915827E−02 4.2874384E−03 11 −1.5622319E+004.9289533E−01 −1.0300562E−01 1.2828503E−02 −7.2029221E−04

TABLE 9 EXAMPLE 5 Si Ri Di Ndj νdj 1(APERTURE ∞ −0.209 STOP) *2 1.440040.729 1.54488 54.87 *3 44.97281 0.047 *4 14.37515 0.274 1.63351 23.63 *52.58212 0.471 *6 −36.18914 0.276 1.63351 23.63 *7 −271.48046 0.299 *8−2.93991 0.684 1.54488 54.87 *9 −1.35014 0.290 *10 1.93295 0.304 1.5448854.87 *11 0.94669 0.543 12 ∞ 0.300 1.56700 37.80 13 ∞ 0.530 14 ∞*ASPHERIC SURFACE

TABLE 10 EXAMPLE 5 • ASPHERIC SURFACE DATA SURFACE NUMBER KA A3 A4 A5 A62 2.3902366E−01 0.0000000E+00 1.8557814E−01 −3.4110518E+00 3.4890992E+013 9.6398649E+02 0.0000000E+00 −3.5676098E+01 9.6130869E−01−3.3933430E+00 4 −2.0713292E+03 0.0000000E+00 −3.3955127E−012.8479607E−01 9.7978257E+00 5 2.5284331E+00 0.0000000E+00 −1.6273463E−016.3655297E−01 −1.3925927E+00 6 −1.9339289E+04 0.0000000E+00−2.3814251E−01 −1.5782671E+00 6.1815977E+00 7 6.1809920E+040.0000000E+00 −7.1303394E−01 3.9943636E+00 −2.5827434E+01 8−1.1963048E+01 0.0000000E+00 −3.4612488E−01 1.2695775E+00 −7.6159464E+009 −1.9655437E+00 0.0000000E+00 −2.5881030E−01 −1.2772538E−014.2742800E+00 10 −4.0189180E+01 0.0000000E+00 −4.8336115E−02−9.6301364E−01 3.4401355E+00 11 −2.4658729E+00 0.0000000E+00−7.7258547E−01 1.5377560E+00 −2.1628441E+00 A7 A8 A9 A10 A11 2−2.2408798E+02 9.8669996E+02 −3.0960106E+03 7.0764486E+03 −1.1895767E+043 9.1693692E+00 −9.5146073E+00 −4.4111845E+00 1.2937012E+01−3.2178751E+00 4 −8.9993384E+01 4.4139598E+02 −1.4140205E+033.2058276E+03 −5.3234937E+03 5 4.9547238E−01 7.4926708E+00−1.5579924E+01 7.4867950E+00 1.0794318E+00 6 −6.5042614E+00−8.9113565E+00 2.3115341E+01 −7.4604600E+00 −9.4087366E+00 71.1912972E+02 −3.9344144E+02 9.4990689E+02 −1.6904954E+03 2.2102411E+038 3.1978278E+01 −9.3122544E+01 1.9618996E+02 −3.0446017E+023.4847079E+02 9 −1.8568030E+01 4.8229934E+01 −8.7555375E+011.1652250E+02 −1.1462128E+02 10 −7.9817953E+00 1.4356583E+01−1.9322541E+01 1.8943040E+01 −1.3378668E+01 11 3.2742790E+00−4.9854876E+00 6.0674115E+00 −5.3967345E+00 3.4438592E+00 A12 A13 A14A15 A16 2 1.4624118E+04 −1.2810293E+04 7.5616085E+03 −2.6868648E+034.3249165E+02 3 1.4215399E+01 −5.4309560E+01 6.1957114E+01−2.8144693E+01 4.0219443E+00 4 6.4837766E+03 −5.6367819E+033.2960713E+03 −1.1543196E+03 1.8183932E+02 5 1.1772461E+01−1.5397171E−01 −3.4701483E+00 9.4434095E+00 −2.0949539E+00 6−1.2078013E+01 3.3758248E+01 −2.0699800E+01 3.5999944E+00 −7.5618132E−027 −2.0922929E+03 1.3922438E+03 −6.1628159E+02 1.6281359E+02−1.9481771E+01 8 −2.9104817E+02 1.7326243E+02 −7.0009861E+011.7264788E+01 −1.9626787E+00 9 8.2164729E+01 −4.1541499E+011.3969688E+01 −2.7894233E+00 2.4855912E−01 10 6.7106418E+00−2.3250402E+00 5.2826891E−01 −7.0917564E−02 4.2837975E−03 11−1.5622341E+00 4.9290080E+01 −1.0300573E−01 1.2828561E−02 −7.2041132E−04

TABLE 11 VALUES IN CONDITIONAL EXPRESSIONS EXPRES- SION EXAM- EXAM-EXAM- EXAM- EXAM- NUMBER PLE 1 PLE 2 PLE 3 PLE 4 PLE 5 f 4.176 4.1424.142 4.141 4.139 Bf 1.371 1.350 1.362 1.340 1.277 L 4.745 4.724 4.7364.714 4.651 FNo. 2.19 2.17 2.20 2.19 2.20 2ω 71.0° 71.4° 71.4° 71.2°71.2° f1 2.796 2.763 2.830 2.767 2.714 f2 −5.502 −5.081 −5.485 −4.994−5.013 f3 −25.305 −265.843 −92.327 −395.916 −65.941 f4 2.646 2.755 2.7682.777 3.979 f5 −2.579 −2.579 −2.614 −2.612 −3.820 f/f45 1 0.170 0.0630.084 0.072 0.065 f/f4 2 1.579 1.503 1.496 1.492 1.040

What is claimed is:
 1. An imaging lens substantially consisting of, inorder from an object side, five lenses of: a first lens that has apositive refractive power and has a meniscus shape which is convextoward the object side; a second lens that has a negative refractivepower; a third lens that has a negative refractive power; a fourth lensthat has a positive refractive power; and a fifth lens that has anegative refractive power and has an object side surface and an imageside surface which have aspheric shapes, wherein the followingconditional expressions (1) and (2) are satisfied:0.043<f/f45<0.186  (1),and0.961<f/f4<1.785  (2), where f is a composite focal length of a wholesystem, f45 is a composite focal length of the fourth and fifth lenses,and f4 is a focal length of the fourth lens.
 2. The imaging lens, asdefined in claim 1, wherein an image side surface of the third lens hasan aspheric shape, an intersection point between the image side surfaceof the third lens and a principal ray with a maximum angle of view ispositioned on the object side of an intersection point between the imageside surface of the third lens and an optical axis, and an intersectionpoint between an object side surface of the third lens and the principalray with the maximum angle of view is positioned on the object side ofan intersection point between the object side surface of the third lensand the optical axis.
 3. The imaging lens, as defined in claim 1,wherein the fifth lens has a meniscus shape which is convex toward theobject side, and each of the object side surface and the image sidesurface has an aspheric shape which has at least one extreme point. 4.The imaging lens, as defined in claim 1, wherein among absolute valuesof respective focal lengths of the first to fifth lenses, an absolutevalue of a focal length of the third lens is the maximum.
 5. The imaginglens, as defined in claim 1, wherein the fourth lens has a meniscusshape which is convex toward an image side.
 6. The imaging lens, asdefined in claim 1, wherein the following conditional expression isfurther satisfied:0.053<f/f45<0.178  (1-1).
 7. The imaging lens, as defined in claim 1,wherein the following conditional expression is further satisfied:1<f/f4<1.681  (2-1).
 8. The imaging lens, as defined in claim 1, whereinthe following conditional expression is further satisfied:0.063<f/f45<0.17  (1-2).
 9. The imaging lens, as defined in claim 1,wherein the following conditional expression is further satisfied:1<f/f4<1.58  (2-2).
 10. The imaging lens, as defined in claim 1, furthercomprising an aperture stop that is disposed on the object side of anobject side surface of the second lens.
 11. An imaging apparatuscomprising: the imaging lens, as defined in claim 1.